US2939323A

US2939323A - Overrunning clutch

Info

Publication number: US2939323A
Application number: US710049A
Authority: US
Inventors: Kochendorfer Heinrich
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1957-01-24
Filing date: 1958-01-20
Publication date: 1960-06-07
Anticipated expiration: 1977-06-07
Also published as: FR1189747A; GB833123A; NL97063C

Description

June 7 1960 H. KOCHENDRFER 2,939,323

OVERRUNNING CLUTCH Filed Jn. 2o, 195e www 5. @zu

Min-J7 backs.

United States Patent O OVERRUNNING CLUTCH Heinrich Kochendrer, Fellbach, Germany, assigner to Robert Bosch G.m.b.H., Stuttgart, Germany Filed Jan. 20, 1958, Ser. No. 710,049

Claims priority, application Germany Jan. 24, 1957 4 Claims. (Cl. 74-6) The present invention relates to overrunning clutches. More particularly, the present invention relates to overrunning clutches which are adapted to be used with the starting motor of an internal combustion engine.

Overrunning clutches of this type have several draw- In the first place the power is transmitted through Asuch clutches in a very sudden manner which stresses the parts to a greater extent than where the load is transmitted in a gradual manner, and in the second place :such clutches are very noisy in their operation.

One of the objects of the present invention is to provide an overrunning clutch arrangement which is capable :of transmitting power in a smooth manner free of shock.

Another object of the present invention is to provide an overrunning clutch arrangement which is far quieter in its operation than conventional overrunning clutches.

Still another object of the present invention is to provide a structure capable of accomplishing the above objects and at the same time composed of simple and ruggedly constructed elements which are very reliable in operation and which can be used wherever conventional overrunning clutches are used.

With the above objects in view the present invention includes in an overrunning clutch arrangement of the above type inner and outer clutch races which are coaxial with each other and one of which drives the other through motion transmitting elements which are located between the races. the driven race through the motion transmitting elements until the driven race turns at a faster speed than the driving race. In accordance with the present invention a transmission means cooperates with these races to transmit a drive therethrough, and the transmission means is connected with the races in such a way that the outer race is free to elastically expand due to forces applied thereto by the motion transmitting elements during the time that the driving race drives the driven race.

The novel features which are considered as character. istic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Pig. 1 is a partly sectional elevational view of an overrunning clutch arrangement according to the presenty invention shown in combination with fragmentarily illustrated parts which cooperate with the clutch arrangement; and

Fig. 2 is a transverse sectional view of the clutch taken along line II-II of Fig. 1 in the direction of the arrows.

Referring to the drawing, the electric starting motor 11 has an armature shaft 10 which is the drive shaft froml which the drive is transmitted to an internal combustion engine, lfor example, for starting the same. One end of the drive shaft of the starting motor 11 is turnably sup- ,.ported in a bearing 12 which forms a housing for the As is well known the driving race will drive- 2,939,323 Patented June 7, 1960 "ice 2 overrunning clutch arrangement and which is centered and fixed to the housing 13 of the starting'motor 11.

The shaft 10 is provided with a smooth cylindrical portion 14 which is surrounded by aV pinion 15 which is capable of turning freely on and axially shifting on the cylindrical portion 14 of the shaft l10. This shaft 10 also has a portion 16 surrounded bya sleeve 17 through which the shaft 10 extends in a manner shown in Fig. 1. This portion 16 of the shaft 10 is formed with a thread of a pitch which is large enough to permit the sleeve 17 to shift axially on the shaft 10 when an axial force is applied to the sleeve 17, this sleeve having a projection extending into the thread of large pitch which is formed on the shaft 10 at the portion l'thereof.

The pinion 15 is integrally connected with an inner race 18 of the overrunning clutch of the present invention, and this inner race 18 is therefore also axially shiftable and freely turnable with respect to the shaft 10. This inner race 1S is the driven race of the clutch. The race 18 is surrounded by an outer driving race 20 which is coaxial with the inner race 18 and which is formed with a plurality of cutouts 21 extending radially into the outer race 20 from the inner periphery thereof, as is most clearly shown in Fig. 2. The cutouts 21 are angularly displaced with respect to each other by about the axis of the outer race 20, and there are four such cutouts 21 each of which extends axially along the entire length of the outer race from its left to its right face, as viewed in Fig. 1. In these cutouts 21 of the outer driving race 20 of the overrunning clutch are respectively located the cylindrical rollers 22 which form motion transmitting elements for transmitting a drive from the outer race 20 to the inner race 18 as long as the latter is not turned by the internal combustion engine at a speed'faster than the outer race.

Each of the cutouts 21 is limited by a pair of end faces 24 and 25 and by a surface 23 extending between the end faces 24 and 25 directed toward the innerk race 18, and extending along a path which is eccentric with respect to the axis of the clutch. The radial length of the end face 24 of each recess 21 is shorter than the radial length of the end face 25 thereof so that each recess 21 is of a tapering wedge-shaped configuration and becomes smaller in cross section toward its end face 24. The outer race 20 is formed with bores 26 in which tubes 27 are slidable and in which are located springs 28 which respectively extend into and engage the end walls of the tubes 27 for urging the latter into the cutouts 21, respectively, and these end walls of the tubes 27 engage theh rollers 22 for urging the latter toward the end faces 24 of the cutouts 21, respectively. Thus, the springs 28 urge the rollers 22 into wedging engagement between l the inner and outer races of the overrunning clutch.

In accordance with the present invention the drive is transmitted through the clutch in a manner which does not prevent the outer race 20 from expanding. This transmission through the clutch is obtained through the connecting means which interconnects the outer driving race 20 with the sleeve 17. This structure includes an annular ange 29 which is fixed to the sleeve 17 at the left end thereof, as viewed in Fig. 1. This flange 29 is provided at its left side face, as viewed in Fig. 1, with a plurality of projections 30 which respectively extend into the cutouts 21, so that there is between the flange 29 and the outer race 20 a connection in the nature of a dog clutch drive. Inasmuch as the projections 30 extend into the cutouts 21 they do not in any way prevent radial expansion of the ring 20. The projections 30 are elongated and in each opening 21 the projection 30 engages the end faces 24 and 25 thereof so that there is a positive driving engagement between the ring 20 and the ange f 29.Y The right end faces of the cylindrical rollers 22, as

viewed Vin Fig. l, engage the'left endfaces ofthe projections 30, and the clutchincludes an annular ring 31 which engages the left en d faces of ythe rollers V2,2, as

the clutch -has inwardly -direeted annular flanges at Y its opposite ends respectively engaging 'the .flange 2 9, .on the one`hand, and the pair ofha'lf rings 32, on the lother hand, so that the s'leevelY holds the `clutch assemblyY together.` The sheet metal sleeve 34 does not resist ,radial expansion'of theV outer raefZO to anyiappreciable degree. The sleeve`17 is snrroundedfby atwo-part ring 35 and a bifurcatedarm ofja twofarnted'lever 36 cooperates with the ringf35 for shifting the latter. axially in aknown way. The '1evervl36 is pivotally supported by a pivot pin 38,

' and when the 'lever 36is turned in a clockwise direction,

as view .edin ,lig.- 1, as by energizing of a solenoid, Vfor example, when the starter buttonlof Zan automobile or the ylikeislpgresseithen.the assembly on the s'haftl!) is shifted to ythe'left.sofas to place the pinion 1 5 in vmesh with the rgear 37, so that the drive will'be transmitted from the pinion to thegear 37, This gear 37 Yformspart `of an unillustrated vinternal combustion engine,'and may form part of the flywheel thereof, for example.

The above-described structure operates as follows: When the enginei sto he started and after the pinion 15 .meshes with the vgear 37 kthe manner describedV be-started. At this time the'outer race Ztl is capable of elastically yielding `in response to the pressure applied thereto by .therollers 22 so that the outer .race 20 elastif cally expands at thistime, andit will be noted that the driving engagement between the 'iange 29 and the outer race 2 0 tdoes notin any way prevent such expansion of the latter. In yother words the projection of the .projecf tions 3 0 into the 4cutouts 2f 1 ,-respectively, in accordance the outwardradial.expansionof the'ring 20. As a result of this elastic yieldability of theouter race of the clutch, the clutch ofthe presentinvention operates in a smoother manner than aconventional clutch andalsofis farquieter than a conventional clutch.

VIt'will be understood fthateac'h of the elements describedabove or two or more together, may also nd a useful application in other types of overrunning clutches differing from the typesdescribed above.

`While the invention has ybeen illustrated-and described asembodied in overrunning clutches of startingmotors, it is not intended to be limited to the details shown, since various modifications .and .structural changes may be made without departing in anyway-from the spirit of the present invention.`

' `Without further analysis, the Vforegoing will so fully reveal the gistof the present inventionthat others c an Y by vapplyingcurrent knowledge readily adapt it for various applications without omitting Y features that, from the standpoint lof prior art, fairly constitute essential characteristics of the genericv orspeciic aspects of this invention and, therefore, suchV adaptations should and arein-Y tended'tojbe.comprehended withinthefmeaning andrange of equivalenceof thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. In an overrunning clutch arrangement for use with the lstarting motor for an internal combustion engine or the like, in combination, a drive shaft adapted to be connected to said starting motor to be driven thereby with a given speed; an inner driven race freely turnable'on said drive shaft; a pinion xed to said inner race, said pinion being adapted to be connected to saidengine; an outer driving race, said outer race ha- Ving free lateral' end faces extending vfrom the inner tothe outer periphery thereof coaxial with said inner race and beingadaptedito be connected to said drive shaft; motion'transmitting elements located between Asaidraces for transmitting adrive .from said driving to said driven race until said driven race is turned by said engine at a faster speedthan said driving race is driven by said starting motor; and connecting means connecting said outer driving racev with Vsaidshaft for transmittinga drive from said Vshaft to said outer race without preventing radial expansion .of said outer race due Vto pressure applied theretoby .said motion transmitting velen` 1 en ts 'during the time that said outer driving race drives said inner .drven race, .said motion .transmitting elements ,having a length only slightly smaller Vthan the width of said outer race so fthat pressure applied to said outer race'by said motion transmitting elements Vwillbe applied substantially over the whole width ofsaidouter race s o as tocause uniform radial expansion thereof to thus providefor a shock free engagement of the outer race byrsaidmotion transmitting elements and even wear of the latter. v

2. In an overrunning clutch arrangement as Vrecited in claim 1, ysaid outer driving race being formed Vwith a Y plurality of cutouts .extending radially'outwardly from the inner peripheryof said outer race and said connecting means including .a flange surrounding and connected to said shaft to be rotated therebyand having a plurality of projections respectively extending into said cutouts so that said outer `race rotates with vsaid flange While at the same time being free to expand radially.

3;,.11n an Overrnnning clutcharrangement'for use with thestarting motor of an internal combustionengine or the like, in combination, a drive shaft; an inner race freely turnable on s aid driveshaft; a pinion txed'to said inner race to rotate therewith, said pinion being adapted to 'be vczonnected to said engine; an outer driving race surrounding and coaxial withsaid inner race having Yfree lateral end Qfaces extending ,from the tinner to the outer periphery thereof and .said outer race being formed with a plurality of cutouts extending radially into said outer race from the inner peripherythereof and Vbeing adapted to'be connectedto said drive shaft; a plurality of motion transmitting roller elements located `in said cutouts for transmitting a drive from'sad outer to vsaid Vinner race until therlattersis turned by said engine at a speedfaster than said outer race is driven by said starting 'motor;` and a driveange Surrounding said shaft and connected thereto tojbe rotated thereby, said ange having a plurality of projections respectively extendinginto said cutouts' in which said rollersare located for transmitting a drive from theshaft tosaid outer race so that the latter can drive said inner face through said rollers, .said outer, race being free to yexpand radially due to vpressure applied theretoby said rollers during drivingofsaid 'inner race by said outer race, said -motion transmitting elementshavngalength .0,I11Y slightlysmaller than'the lwidth .of said outer race so that pressure applied to said outerrace by said motion transmitting elements will be applied substantially over the-whole width of said outer race so as to causeuniform radial expansion thereofto thus provide fora shock free engagement ofthe outer race by said motion. transmit ti 1gelements and even wear-of the latter.

4. In an overrunning clutch arrangementfor use with a stalngniotor of an internal combustion engine, or the like, in combination, a ,sleeve and -a. drive shaft ex- 5 tending through said sleeve, said drive shaft and sleeve respectively having inner and outer surfaces directed toward and located closely adjacent to each other, one of said surfaces being formed with a thread and the other of said surfaces having a projection extending into said thread so that the drive shaft and sleeve are threadedly connected to each other and said thread having a pitch large enough to provide axial shifting of said sleeve on said shaft in response to axial pressure applied to said sleeve, said drive shaft adapted to he driven by said starting motor; a ange xed to and surrounding said sleeve and having a plurality of projections extending from one of its side faces; an outer clutch race located coaxially around said shaft next to said one side face of said flange and being formed with a plurality of cutouts extending radially into said outer race from the inner periphery thereof and respectively receiving said projections of said ange so that the latter is in driving engagement with said outer race, said outer race having free lateral end faces extending from the -innerto the outer periphery thereof; an inner race surrounding said shaft and being freely turnable and axially shiftable with respect thereto and surrounded by said outer race, said inner race adapted to be connected to said engine; a plurality of motion transmitting rollers located in said cutouts of said outer race for transmitting a drive from said outer to said inner race as long as said inner race is not turned at a faster speed by lsaid engine than said outer race is driven by said starting motor; and a pinion `fixed to said inner race for transmitting a drive therefrom, the connection of said outer race with sa-id flange through the projections of the latter freeing said outer race for radial expansion due to pressure applied thereto by said rollers while said outer race drives said inner race through said rollers, said motion transmitting elements having a length only slightly smaller than the width of said outer race so that pressure applied to said outer race by said motion transmitting elements will be applied substantially over the whole width of said outer race -so as to cause uniform radial t expansion thereof to thus provide for a shock free engagement of the outer race by said motion transmitting elements and even Wear of the latter.

References Cited in the le of this patent UNITED STATES PATENTS 2,175,876 Chitlon Oct. l0, 1939 2,192,434 Critcheld Mar. 5, 1940 2,211,053 Critchfield Aug. 13, 1940 2,481,249 Schneider et al Sept. 6, 1946